This invention relates to a device and method for the detection of extravasation and more particularly to the detection of extravasation of ionic and non-ionic contrast media.
Extravasation or infiltration is a complication related to the use of power injectors during contrast media injection procedures. When an extravasation occurs, contrast is injected into the tissue surrounding the blood vessel, instead of into the blood vessel itself. The causes for extravasation vary, ranging from operator error in placement of the needle to physiological limitations of the blood vessel to tolerate the rate of fluid administration.
Complications related to extravasation may be quite severe and may include tissue necrosis. This may require reconstructive surgery to repair.
Presently, the only method for detecting an extravasation is for the operator to visually observe it. However, by the time an extravasation is visually observable, much of the previously discussed damage may have occurred.
Accordingly, it is an object of the present invention to provide a safe, efficient, inexpensive and reliable means for the early detection of extravasations.
A very large number of contrast media injection procedures are undertaken each year in the United States; something in the order of ten million. Less than 0.2% of these procedures result in an extravasation. Yet the absolute number is substantial because the base number is so large. The occurrence of an extravasation requires that the procedure be terminated and reinstituted. Accordingly, in a normal situation where an extravasation occurs, early detection is important from the point of view of minimizing the impact on the patient, saving time and providing a timely reinstitution of the procedure.
Although extravasation is not life-threatening, when it does occur it causes discomfort to the patient. It requires a great deal of attention from the doctor and usually means that a procedure has to be interrupted. Thus, it is important that any extravasation detection technique avoid a false indication of extravasation.
In relatively rare cases the extravasation can be quite harmful to the patient. Therefore early detection will avoid patient trauma or other injury.
The false detection of an extravasation results in terminating a procedure. Starting the procedure constitutes unnecessary trauma to the patient and expense. Therefore, any detection technique that gives a noticeable number of false indications will not be used by the doctor.
Accordingly, it is important that any detection technique to be acceptable combine an extremely small number of false indications of extravasation coupled with a reasonably high specificity to the extravasation event being detected.
The relatively large number of contrast media injections undertaken coupled with the relatively small percentage of extravasations that occur means that any procedure to be acceptable to the medical profession has to be non-invasive.
It is an accepted fact that any invasive procedure carries with it risks and trauma. They are to be avoided unless the benefit trade-off warrants such.
Thus, in order for an extravasation detection technique to be acceptable in this context, it must meet the following objectives.
First, it has to be inexpensive and be a disposable single use item.
Second, it must be relatively acceptable to the patient. Therefore, it should be non-invasive and create no pain or other patient problem.
Third, it has to be easy for the technician or doctor to use and readily fits within the procedure involved in the contrast media injection routine.
Fourth, and perhaps more importantly, it must provide next to no false indications of extravasation. A false indication would mean stopping a procedure which did not have to be stopped. Thus it follows that the technique must be specific to extravasation and non-responsive to other phenomenon such as the patient moving his or her arm.
Only a device that meets the above criteria (a) will be safe, (b) have technicians and doctors willing to use it, (c) have patients accept it and (d) have it come within the economic requirements of the institution providing the media injection procedure.